Integrated circuit components, such as integrated circuit die, are attached to substrates, such as printed circuit boards, to form microelectronic assemblies. The integrated circuit components typically include bond pads that are electrically and physically connected to bond pads located on the substrate. This connection can be accomplished by solder bumps.
One technique proposed to attach an integrated circuit component to a substrate is to dispose solder bumps onto the bond pads on the integrated circuit component. The component is then placed onto the substrate such that the solder bumps register with and contact bond pads on the substrate. This preassembly is then heated to reflow the solder bumps. The preassembly is then cooled, whereupon the solder bonds to the bond pads on both the die and the substrate to form solder bump interconnections which electrically and mechanically attach the integrated circuit component to the substrate. The solder bump interconnections extend across the gap formed between the die and the substrate.
One problem faced by the aforementioned assembly is that the solder bump interconnections, because they act to provide the mechanical attachment of the component, need to be reinforced. One such method to enhance the reliability of the assembly is to dispense a polymeric encapsulant in the gap between the component and the substrate. This is accomplished by dispensing a polymeric precursor about the perimeter of the attached component and allowing capillary action to draw the encapsulant into the gap. The assembly is then heated to a temperature sufficient to cure the precursor to form a polymeric encapsulant. The polymeric encapsulant acts to provide enhanced reliability to the assembly by distributing the stresses from the solder bumps and also by encapsulating the solder bump interconnections so that they are not subject to environmental degradation.
Therefore, a need exists for a microelectronic package and the method for forming a package for attaching an integrated circuit component to a substrate that provides enhanced reliability to the solder bump interconnections and also provides protection for the back side of the integrated circuit die. Further, a need exists to accomplish the reinforcement of the solder bumps and the protection of the back side of the integrated circuit die using a less complex manufacturing process.